LM27313: What is the ratio relationship between Vin and FB in LM27313 boost chip?

Depeng Man

Intellectual 2030 points

Part Number: LM27313

Hello Team,

What is the ratio relationship between Vin and FB in LM27313 boost chip?

I have a 12V boost 24V power supply project on my side, currently I only see one in the specification book Δ VFB/ Δ The relationship between VINs, and the resistance value of R1 is determined by the formula R1 = R2 x ((VOUT / VFB)1). I am not sure how to set Vfb at this time.

There is no recommendation for L1 inductance selection, the load current is about 600mA.

Best Regards,

James

over 2 years ago

0 Lei Zhong over 2 years ago

TI__Genius 12130 points

Hi James,

When the device is working properly, the VFB should always equal to the internal Vref, that is, 1.23V which is a fixed value. And VFB is decided by Vout, R1 and R2. That's how the formula R1 = R2 x ( (VOUT / VFB) − 1 ) comes from.

While working at 12V to 24V, limited by the switching current limit, LM27313 can't generate 600mA Iout. The max Iout is around 300mA.

Regards

Lei

0 Depeng Man over 2 years ago in reply to Lei Zhong

TI__Intellectual 2030 points

Hello Lei,

Thank you for your quick reply.

I've conveyed it to my customer.

Have a good day .

James

0 Lei Zhong over 2 years ago in reply to Depeng Man

TI__Genius 12130 points

Hi James,

Thanks for your feedback.

Regards

Lei

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LM27313: What is the ratio relationship between Vin and FB in LM27313 boost chip?